1. Field of the Invention
The invention relates to an apparatus and a method for detecting the temperature of a room.
Such apparatuses and methods are advantageously used in buildings for detecting an average temperature in a room.
2. Description of the Prior Art
An apparatus for detecting temperature by means of sound waves is known (U.S. Pat. No. 5,349,859), in which the speed of sound in a fluid is detected and the temperature of the fluid is calculated therefrom.
It is also known (U.S. Pat. No. 4,031,756) to use ultrasonic waves to detect the flow speed of air and to calculate the temperature of the air.
In the known apparatuses and methods of detecting temperature by means of sound waves or ultrasonic waves, it is presupposed that the distance which the sound waves or ultrasonic waves cover in the measuring apparatus is precisely known.
The expressions sound or sound wave without further details denote generally hereinafter sound waves in the frequency ranges of audible sound (16 Hzxe2x89xa6fxe2x89xa616 kHz) or ultrasound (f greater than 16 kHz).
The object of the invention is to provide an apparatus and a method of detecting the temperature of a room by means of sound waves, which can also be used when the dimensions of the room are not known.
According to a first aspect of the present invention, there is provided apparatus for detecting the temperature of a room including:
means for generating and receiving sound waves,
means for determining the transit time of the sound waves for a certain distance in the room,
means for calculating the temperature of the room by means of the ascertained transit time of the sound waves for the distance in the room, and
means for automatically carrying out an approximation procedure for ascertaining the distance.
According to a second aspect of the present invention, there is provided a method of detecting the temperature of a room by means of sound waves including the method steps of:
emitting sound waves towards a delimiting surface of the room, which reflects sound waves;
receiving reflected sound waves;
calibrating a value for the spacing at which the delimiting surface is from the transmitting or receiving device for the sound waves; and
calculating the temperature of the room using the spacing and the transit time of the sound waves for the spacing.
According to a third aspect of the present invention, there is provided an installation for regulating and/or controlling room climate parameters, including an apparatus in accordance with the first aspect of the invention.
Advantageous features are set forth in the dependent claims.